Modular GE deepwater tree reduces footprint, weight

GE Oil & Gas launched its VetcoGray DHXT deepwater horizontal tree and integral control system at the 2010 Offshore Technology Conference (OTC), held 3-6 May in Houston, Texas.

The DHXT, which can operate in water depths up to 10,000 ft and at pressures up to 15,000 psi, features a design that the company says can reduce the industry-standard horizontal tree footprint by 12% and weight by 10%. The D-Series package includes the integral VetcoGray ModPod, a subsea control module that is powered by SemStar5, representing a new generation of open-architecture subsea control and instrumentation systems.

The DHXT has three primary configurations:

1. DHXT-SP: a standard production tree that’s compact, lightweight and designed for the lowest installed cost and reliability. A modular concept is used for all major components of the tree.

2. DHXT-EP: an enhanced production tree system with additional functionality. The annulus wing block is extended to include additional valves and sensors for improved annulus pressure management.

3. DHXT-GP: a gas lift production tree system offering further functionality. Additions to the standard system include a gas lift choke, dual-bore flow-line connector and sensors.

The new trees are being manufactured in Houston and Aberdeen, Scotland.

The D-Series package includes the integral VetcoGray ModPod, powered by the VetcoGray SemStar5, a fifth-generation subsea electronics module, for first deployment next year by Statoil’s Tordis Vigdis Controls Modification (TVCM) project in the North Sea, west of Norway.

Featuring a modular design approach, SemStar5 offers open-architecture IP-enabled communication capabilities and infrastructure to support the higher bandwidth requirements of modern instrumentation, while also offering high reliability.

The SemStar5 is being developed and manufactured at GE’ facilities in Nailsea, UK, along with VetcoGray ModPod subsea control modules, and will be shipped to the project site for installation offshore shortly.

The DHXT and subsea system can be monitored remotely from GE’s SmartCenter (Subsea Monitoring and Remote Technology Center), a remote-access data hub connected to subsea field control and instrumentation facilities around the world.

The DHXT deepwater tree with integral control system also features the option for a SemStar5-R, which is a freestanding subsea data hub package designed for installation on subsea trees, manifolds and process facilities. The unit is deployed and retrieved by ROV, with connections to the subsea control and instrumentation system made with wet-mateable ROV-deployed jumpers – using either electrical or fiber-optic connections.

The external package is fully marinized for long-term subsea immersion, and the internal data-hub multiplexing unit is an application-specific configuration of the SemStar5 subsea electronics module.